1. FIELD OF THE INVENTION
The present invention relates to a silver halide photographic material which shows increased interimage effects and has improved sharpness and granularity.
2. DESCRIPTION OF THE PRIOR ART
It is known that upon color development of a silver halide color photographic material, an oxidized aromatic primary amine-based color developing agent and a coupler react to form a dye such as indophenol, indoaniline, indamine, azomethine, phenoxazine and phenazine, thereby producing a color image. In such a system, color reproduction is usually carried out by a subtractive process; silver halide emulsions selectively sensitive to blue, green and red, and yellow, magenta and cyan color image-forming agents in a complementary color relation therewith are used. In the formation of a yellow color image, an acylacetanilide or a dibenzoylmethane-based coupler, for example, is mainly used. In the formation of a magenta color image, a pyrazolone, pyrazolobenzimidazole, pyrazolopyrazole, pyrazolotriazole, cyanoacetophenone or indazolone-based coupler is mainly used, and in the formation of a cyan color image, a phenol or naphthol-based coupler is mainly used.
Each dye formed from the above couplers does not have an ideal spectral absorption spectrum. In particular, magenta and cyan dyes have broad absorption spectra and have a sub-absorption in the short wavelength region, both factors being unsuitable for color reproduction of a color photographic material.
In particular, the sub-absorption in the short wavelength region tends to decrease saturation or chroma. One means to overcome the above problem is to use dyes which exhibit the interimage effect. A decrease in saturation can be improved to a certain extent by using dyes which exhibit the interimage effect.
This interimage effect is described in Hanson et al., Journal of the Optical Society of America, Vol. 42, pp. 663-669, A. Thiels, Zeitschrift fur Wissenschaftliche Photographie, Photophysque und Photochemie, Vol. 47, pp. 106-118 and pp. 246-255, and so forth.
U.S. Pat. No. 3,536,486 discloses a method in which the interimge effect is obtained by introducing a diffusible 4-thiazoline-2-thione into an exposed color reversal photographic element, and U.S. Pat. No. 3,536,487 discloses a method in which the interimage effect is obtained by introducing a diffusible 4-thiazoline-2-thione into an unexposed color reversal photographic element.
Japanese Patent Pulication No. 34169/73 describes that the interimage effect is markedly exhibited by allowing an N-substituted 4-thiazoline-2-thione compound to be present at the time of the reduction of silver halide into silver through development of a color photographic material.
Research Disclosure, No. 131, Clause 13116 (1975) discloses that a colloidal silver containing layer can be provided between a cyan layer and a magenta layer of a color reversal photographic element to obtain the interimage effect.
In addition, U.S. Pat. No. 4,082,553 discloses a method of obtaining the interimage effect where, in a color reversal light-sensitive material which has a layer arrangement that permits the transfer of iodine ions during development, latent image-forming silver haloiodide particles are incorporated in one layer of the material, and latent imageforming silver halide particles and silver halide particles, the surface of which is fogged so as to render the same capable of being developed regardless of image exposure are incorporated in another layer.
The above methods, however, fail to provide a sufficient interimage effect. Further, the use of a colloidal silver containing layer, the incorporation of fogged silver halide particles and so forth yield the serious disadvantage in a color reversal light-sensitive material that a reduction in color density is caused.
It is also known that the interimage effect can be obtained by using a coupler (DIR coupler) capable of releasing a development inhibiting substance (such as benzotriazole derivatives and mercapto compounds) during the coupling reaction with an oxidized product of a color developing agent at the color developing step, or by using hydroquinone compounds, for example, capable of releasing a development inhibiting substance such as iodide ions and mercapto compounds. Use of these compounds, however, is associated with serious desensitization, or causes a reduction in color density. Thus the compounds are limited in their practical use.
A DIR coupler exhibits the interimage effect by inhibiting development at color developing. However, even if a DIR coupler is applied to a color reversal lightsensitive material, color development is hardly inhibited and thus the interimage effect is not exhibited to any substantial extent.